Sareen et al., 2012). SMA is a genetic childhood disease characterized by motor neuron loss that is believed to be due to a reduction in the amount of survival motor neuron (SMN) protein in motor neurons. She reported that astrocyte activation could be a non-cell-autonomous contributor to disease, as when SMN is reduced in hiPSC astrocytes and there is increased astrocyte reactivity, and that co-culture of neurons with SMA astrocytes leads to neuronal phenotype. Together, this work begins to answer why motor neurons are uniquely vulnerable in SMA when SMN is a ubiquitously expressed protein, as it may be that increased astrocyte reactivity ultimately leads to the reduced synaptic puncti observed in SMA hiPSC motor neurons.
